A semiconductor device package may include at least one semiconductor device mounted on a substrate having circuitry. The circuitry of the substrate may include conductive traces and/or conductive pads. The conductive pads may be electrically connected to the semiconductor device. Solder mask is used to cover the conductive traces and/or portions of peripheral areas of the conductive pads for protection. Moreover, solder mask can also control warpage of the semiconductor device package.
However, structural defects, e.g. crack or delamination, may occur around or at boundaries between the conductive pads and the solder mask due to a mismatch of coefficients of thermal expansion (CTEs) or warpage during thermal cycles of the manufacturing process. The crack or delamination between the conductive pad and the solder mask may cause reliability issue. For example, the solder for joining conductive pads of the semiconductor device to the conductive pads of the substrate may flow into the crack and make contact with nearby circuits, resulting in short circuit. The solder flowing into the crack may also aggravate the crack issue.